MTD Yard Machines LT31 User manual

Brand: MTD

Model: Yard Machines LT31

Category: Grass trimmers

Type: User manual

Operator’s Manual

IMPORTANT: Read safety rules and instructions carefully before operating equipment.

PRINTED IN U.S.A.

PART NO. 769-01389 (12/04)

LT31, LT31C

2-Cycle Petrol

Trimmers

LT31CS

Trimmer /

Brushcutter

INTRODUCTION

TABLE OF CONTENTS

Service Information . . . . . . . . . . . . . . . . . . . . . . . . .2

Rules for Safe Operation . . . . . . . . . . . . . . . . . . . . .3

Know Your Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Assembly Instructions . . . . . . . . . . . . . . . . . . . . . .10

Oil and Petrol Information . . . . . . . . . . . . . . . . . . .15

Starting/Stopping Instructions . . . . . . . . . . . . . . . .16

Operating Instructions . . . . . . . . . . . . . . . . . . . . . .17

Maintenance and Repair Instructions . . . . . . . . . . .19

Troubleshooting Chart . . . . . . . . . . . . . . . . . . . . . .30

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

Copy the serial number

here:

THANK YOU

Thank you for buying this quality product. This modern

outdoor power tool will provide many hours of useful

service. You will find it to be a great labor-saving device.

This operator’s manual provides you with easy-to-

understand operating instructions. Read the whole

manual and follow all the instructions to keep your new

outdoor power tool in top operating condition.

PRODUCT REFERENCES, ILLUSTRATIONS

AND SPECIFICATIONS

All information, illustrations, and specifications in this

manual are based on the latest product information

available at the time of printing. We reserve the right to

make changes at any time without notice.

Reserved.

SERVICE INFORMATION

Service on this unit both within and after the warranty

period should be performed only by an authorized and

approved service dealer.

DO NOT RETURN THE UNIT TO THE RETAILER.

PROOF OF PURCHASE WILL BE REQUIRED FOR

WARRANTY SERVICE.

Before beginning, locate the unit’s model plate. It lists

the model and serial numbers of your unit. Refer to the

sample plate below and copy the information for future

reference.

S/N :

ITEM :

MODEL :

Make sure you carefully read and understand this manual before starting or operating this equipment.

THIS PRODUCT IS COVERED BY ONE OR MORE U.S. PATENTS. OTHER PATENTS PENDING.

Copy the model and parent

part number here:

RULES FOR SAFE OPERATION

READ ALL INSTRUCTIONS

BEFORE OPERATING

• Read the instructions carefully. Be familiar with the

controls and proper use of the unit.

• Do not operate this unit when tired, ill, or under the

influence of alcohol, drugs, or medication.

• Children and teens under the age of 15 must not use

the unit, except for teens guided by an adult.

• All guards and safety attachments must be installed

properly before operating the unit.

• Inspect the unit before use. Replace damaged parts.

Check for petrol leaks. Make sure all fasteners are in

place and secure. Replace parts that are cracked,

chipped, or damaged in any way. Do not operate the

unit with loose or damaged parts.

• Carefully inspect the area before starting the unit.

Remove all debris and hard or sharp objects such as

glass, wire, etc.

• Be aware of the risk of injury to the head, hands and

feet.

• Clear the area of children, bystanders, and pets. At a

minimum, keep all children, bystanders, and pets

outside a 15 m (50 foot) radius; there still may be a risk

to bystanders from thrown objects. Bystanders should

be encouraged to wear eye protection. If you are

approached, stop the unit immediately.

•Use only

2.41mm, 0.095 inch (for the brushcutter

LT31CS), or 2.03 mm, 0.080 inch (for trimmers

LT31 & LT31C), diameter original equipment

manufacturer replacement line. Never use metal-

reinforced line, wire or rope. These can break off and

become dangerous projectiles.

• Squeeze the throttle control and check that it returns

automatically to the idle position. Make all adjustments

or repairs before using unit.

•

Trimmer models LT31 & LT31C only: These units

was not designed to be used as a brushcutter. Do not

attach or operate these units with any type of

brushcutting blade or brushcutting attachment.

SAFETY WARNINGS FOR PETROL UNITS

• Store petrol only in containers specifically designed

and approved for the storage of such materials.

• Avoid creating a source of ignition for spilled petrol.

Do not start the engine until petrol vapors dissipate.

SYMBOL MEANING

The purpose of safety symbols is to attract your

attention to possible dangers. The safety symbols,

and their explanations, deserve your careful attention

and understanding. The safety warnings do not by

themselves eliminate any danger. The instructions or

warnings they give are not substitutes for proper

accident prevention measures.

NOTE: Advises you of information or instructions vital to

the operation or maintenance of the equipment.

SYMBOL MEANING

When using the unit,

you must follow the

safety rules. Please read these instructions

before operating the unit in order to ensure

the safety of the operator and any bystanders.

Please keep these instructions for later use.

WARNING:

• IMPORTANT SAFETY INSTRUCTIONS •

Failure to obey a

safety warning can

result in injury to yourself and others.

Always follow the safety precautions to

reduce the risk of fire, electric shock and

personal injury.

WARNING:

Failure to obey a

safety warning will

result in serious injury to yourself or to

others. Always follow the safety precautions

to reduce the risk of fire, electric shock and

personal injury.

DANGER:

Failure to obey a

safety warning may

result in property damage or personal injury

to yourself or to others. Always follow the

safety precautions to reduce the risk of fire,

electric shock and personal injury.

CAUTION:

Indicates

danger,

warning or caution. Attention is required in

order to avoid serious personal injury. May

be used in conjunction with other symbols

or pictographs.

SAFETY ALERT:

Petrol is highly

flammable, and its

vapors can explode if ignited. Take the

following precautions:

WARNING:

Read the Operator’s Manual(s) and follow all

warnings and safety instructions.

Failure to do so can result in serious injury to the

operator and/or bystanders.

• Always stop the engine and allow it to cool before

filling the feul tank. Never remove the feul tank cap or

add fuel when the engine is hot. Never operate the unit

without the fuel cap securely in place. Loosen the fuel

tank cap slowly to relieve any pressure in the tank.

• Add fuel in a clean, well-ventilated outdoor area where

there are no sparks or flames. Remove the fuel cap

slowly, and only after the engine stops. Do not smoke

while fueling or mixing fuel. Wipe up any spilled fuel

from the unit immediately.

• Avoid creating a source of ignition for spilled fuel. Do

not start the engine until fuel vapors dissipate.

• Move the unit at least 9.1 m (30 feet) from the fueling

source and site before starting the engine. Do not

smoke. Keep sparks and open flames away from the

area while adding fuel or operating the unit.

WHILE OPERATING

• Never start or run the unit inside a closed room or

building. Breathing exhaust fumes can be fatal.

Operate this unit only in a well-ventilated outdoor area.

• Wear safety glasses or goggles that meet ANSI Z87.1

standards and are marked as such. Wear ear/hearing

protection when operating this unit. Wear a face or

dust mask if the operation is dusty.

• Wear heavy long pants, boots, gloves and a long

sleeve shirt. Do not wear loose clothing, jewelry, short

pants, sandals or go barefoot. Secure hair above

shoulder level.

• The cutting attachment shield must always be in place

while operating the unit as a trimmer. Do not operate

unit without both trimming lines extended, and the

proper line installed. Do not extend the trimming line

beyond the length of the shield.

• CLUTCH:

LT31: This unit does not have a clutch. The cutting

attachment continues rotating when the engine is

idling. If it does not, have the unit adjusted by an

authorized service technician.

LT31C & LT31CS: These units have a clutch. The

cutting attachment remains stationary when the engine

is idling. If it does not, have the unit adjusted by an

authorized service technician.

• Adjust the handle to your size in order to provide the

best grip.

• Be sure the cutting attachment is not in contact with

anything before starting the unit.

• Use the unit only in daylight or good artificial light.

• Avoid accidental starting. Be in the starting position

whenever pulling the starter rope. The operator and

unit must be in a stable position while starting. Refer

to Starting/Stopping Instructions.

• Use the right tool. Only use this tool for its intended

purpose.

• Do not overreach. Always keep proper footing and

balance.

• Always hold the unit with both hands when operating.

Keep a firm grip on both handles or grips.

• Keep hands, face, and feet at a distance from all

moving parts. Do not touch or try to stop the cutting

attachment when it rotates.

• Do not touch the engine, gear housing or muffler.

These parts get extremely hot from operation, even

after the unit is turned off.

• Do not operate the engine faster than the speed

needed to cut, trim or edge. Do not run the engine at

high speed when not cutting.

• Always stop the engine when cutting is delayed or

when walking from one cutting location to another.

• If you strike or become entangled with a foreign

object, stop the engine immediately and check for

damage. Do not operate before repairing damage. Do

not operate the unit with loose or damaged parts.

• Stop the unit, switch the engine to off, and disconnect

the spark plug for maintenance or repair.

• Use only original equipment manufacturer replacement

parts and accessories for this unit. These are available

from your authorized service dealer. Use of any

unauthorized parts or accessories could lead to

serious injury to the user, or damage to the unit, and

void your warranty.

• Keep unit clean of vegetation and other materials.

They may become lodged between the cutting

attachment and shield.

• To reduce fire hazard, replace a faulty muffler and

spark arrestor. Keep the engine and muffler free from

grass, leaves, excessive grease or carbon build up.

BRUSHCUTTER LT31CS ONLY:

WHILE

OPERATING WITH CUTTING BLADE

• Read and understand all safety warnings before

operating this unit.

• Always use the shoulder harness when using the

brush blade accessory.

• Keep the J-handle between the operator and cutting

attachment or blade at all times.

• NEVER cut when the cutting blade is 76 cm (30

inches) or more above the ground level.

• Blade thrust may occur when the spinning blade

contacts an object that it does not immediately cut.

Blade thrust can be violent enough to propel the unit

and/or operator in any direction, possibly causing a

loss of control. Blade thrust can occur without warning

if the blade snags, stalls or binds. This is more likely to

occur in areas where it is difficult to see the material

being cut.

• For operation with the brush blade, do not cut

anything thicker than 1/2 inch or a violent kickback

could occur.

RULES FOR SAFE OPERATION

• Do not attempt to touch or stop the blade when it is

rotating.

•A coasting blade can cause injury while it continues to

spin after the engine is stopped or the throttle trigger

is released. Maintain proper control until the blade has

completely stopped rotating.

• Do not run the unit at high speed when not cutting.

• If you strike or become entangled with a foreign

object, stop the engine immediately and check for

damage. Have any damage repaired before attempting

further operations. Do not operate unit with a bent,

cracked or dull blade. Discard blades that are bent,

warped, cracked or broken.

• Do not sharpen the cutting blade. Sharpening the blade

can cause the blade tip to break off while in use. This

can result in severe personal injury. Replace the blade.

• Do not use the cutting blade for edging or as an edger;

severe personal injury to yourself or others may incur.

Use the cutting blade only for the purpose described

in this manual.

• Stop the engine IMMEDIATELY if you feel excessive

vibration. Vibration is a sign of trouble. Inspect

thoroughly for loose nuts, bolts or damage before

continuing. Repair or replace affected parts as

necessary.

RULES FOR SAFE OPERATION

After Use

• Clean cutting blades with a household cleaner to

remove any gum buildup. Oil the blade with machine

oil to prevent rust.

• Lock up and store the cutting blade in an appropriate

area to protect the blade from unauthorized use or

damage.

OTHER SAFETY WARNINGS

• Never store a fueled unit inside a building where fumes

may reach an open flame or spark.

• Allow the engine to cool before storing or transporting.

Be sure to secure the unit while transporting.

• Store the unit in a dry area, locked up or up high to

prevent unauthorized use or damage, out of the reach

of children.

• Never douse or squirt the unit with water or any other

liquid. Keep handles dry, clean and free from debris.

Clean after each use, see Cleaning and Storage

instructions.

• Keep these instructions. Refer to them often and use

them to instruct other users. If you loan someone this

unit, also loan them these instructions.

SAVE THESE

INSTRUCTIONS

SAFETY AND INTERNATIONAL SYMBOLS

This operator's manual describes safety and international symbols and pictographs that may appear on this product.

Read the operator's manual for complete safety, assembly, operating and maintenance and repair information.

RULES FOR SAFE OPERATION

SYMBOL MEANING

• WEAR HEAD PROTECTION

WARNING: Falling objects can

cause severe head injury. Wear head

protection when operating this unit.

• ON/OFF STOP CONTROL

ON / START / RUN

• ON/OFF STOP CONTROL

OFF or STOP

•HOT SURFACE WARNING

Do not touch a hot muffler or cylinder.

You may get burned. These parts get

extremely hot from operation. They

remain hot for a short time even after

the unit is turned off.

• SHARP BLADE

WARNING: Sharp blade on cutting

head guard. To prevent serious

injury, do not touch line cutting blade.

• LT31CS ONLY: Bruscutters

Replace dull blade

Do not sharpen the cutting blade.

Sharpening the blade can cause the

blade tip to break off while in use. This

can result in severe personal injury.

• CHOKE CONTROL

1. FULL choke position.

2. PARTIAL choke position.

3. RUN position.

• LT31CS ONLY: TRIMMER/

BRUSHCUTTER SAFETY

WARNING: Thrown objects and

rotating cutter can cause severe injury.

Keep bystanders, especially children

and pets, at least 15 meters (50 ft.)

away from the cutting area. The cutting

head guard must be used when using

the trimmer cutting head.

SYMBOL MEANING

• SAFETY ALERT SYMBOL

Indicates danger, warning, or

caution. May be used in conjunction

with other symbols or pictographs.

•WARNING - READ

OPERATOR'S MANUAL

Read the Operator’s Manual(s) and

follow all warnings and safety

instructions. Failure to do so can result

in serious injury to the operator and/or

bystanders.

• WEAR EYE AND HEARING

PROTECTION

WARNING:

Thrown objects and loud

noise can cause severe eye injury and

hearing loss. Wear eye protection

meeting ANSI Z87.1-1989 standards and

ear protection when operating this unit.

Use a full face shield when needed.

• KEEP BYSTANDERS AWAY

WARNING: Keep all bystanders,

especially children and pets, at least

50 feet (15 m) from the operating area.

• PRIMER

Push primer bulb, fully and slowly,

10 times.

• UNLEADED PETROL

Always use clean, fresh unleaded

petrol.

•OIL

Refer to operator's manual for the

proper type of oil.

• THROWN OBJECTS CAN

CAUSE SEVERE INJURY

WARNING: Keep clear of blower

outlet. Never point the blower at

yourself or others. Objects can be

thrown from blower. Do not operate

unit without proper attachments and

guards in place.

KNOW YOUR UNIT

APPLICATIONS

As a trimmer:

• Cutting grass and light weeds

• Edging

• Decorative trimming around trees, fences, etc.

Fuel Cap

Throttle

Control

D-Handle

Shaft

Grip

Primer

Bulb

Blue Choke

Lever

Air Filter/Muffler

Cover

Shaft

Tube

Starter

Rope Grip

Line Cutting Blade

Muffler

On/Off Stop

Control

Cutting Attachment

Trimmer Model

LT31

Take the time to identify the configuration of your unit, which is either a

LT31, LT31C or LT31CS. Use this page, and the two that follow, to

identify which unit is yours, then familiarize yourself with it.

APPLICATIONS

As a trimmer:

• Cutting grass and light weeds

• Edging

• Decorative trimming around trees, fences, etc.

Cutting

Attachment

Shield

Fuel Cap

Throttle

Control

D-Handle

Cutting Attachment

Shaft Grip

Primer

Bulb

Air Filter/Muffler

Cover

Spark Plug

On/Off Stop Control

Shaft

Housing

Starter Rope

Grip

Line Cutting

Blade

Muffler

Support Fitting

Throttle Control

Blue Choke

Lever

KNOW YOUR UNIT

Trimmer Model

LT31C

KNOW YOUR UNIT

APPLICATIONS

As a trimmer:

• Cutting grass and light weeds

• Edging

• Decorative trimming around trees, fences, etc.

As a brushcutter:

• Cutting weeds and light bush of up to 1/2 inch in diameter

Cutting

Attachment

Shield

Fuel Cap

Throttle

Control

J-Handle

Cutting Attachment

Gear Housing

Shaft Grip

Primer Bulb

Air Filter/Muffler

Cover

Spark Plug

On/Off Stop Control

Shaft

Housing

Starter Rope

Grip

Blade Shield /

Shield Mount

Cutting Blade

Line Cutting

Blade

Muffler

Support Fitting

Throttle Lock-Out

Throttle Control

Blue Choke

Lever

Brushcutter

Model

LT31CS

ASSEMBLY INSTRUCTIONS

LT31CS:

J-handle

1. Place the J-handle between the top and middle

clamp pieces (Fig. 3).

(4) Screws

Top Clamp

J-Handle

Middle Clamp

Bottom Clamp

Nuts

2. While holding the three pieces together, install the four

(4) screws through the top clamp and into middle clamp.

NOTE: The holes in the top and middle clamp will line up

only when assembled correctly.

3. Place the clamps and the J-handle over the shaft

housing and onto the bottom clamp.

4. Hold each hex nut in the bottom clamp recess with a

finger. Start screws with a large Phillips screwdriver.

Do not tighten until you make the handle adjustment.

5. Slide the J-handle in or out until the arrow/white line on

the decal touches the clamp assembly (Fig. 4). You must

first loosen the screws if the handle is pre-installed.

Fig. 3

Fig. 4

6. While holding the unit in the operating position (Fig.

27), position the J-handle to the location that provides

you the best grip.

7. Tighten the clamp screws evenly, until the J-handle

is secure.

Decal

INSTALL AND ADJUST THE HANDLE

Use the following information to install or adjust the

handle onto your trimmer. Follow the instructions that

apply to your type of handle.

LT31:

Small D-handle

1. Push the D-handle down onto the shaft housing so

that the handle slants towards the shaft grip (Fig. 1).

The squared bolt hole in the handle is to the right.

2. Insert the shoulder bolt into the squared hole in the

handle and push through. On the left side of the

handle, place the washer on the bolt, then screw the

wing nut onto the bolt. Do not tighten until you make

the handle adjustment.

3. Rotate the D-handle to place the grip above the top

of the shaft housing. Place it a minimum of 15.24 cm

(6 inches) from the end of the shaft grip.

4. While holding the unit in the operating position

(Fig. 27), position the D-handle to the location that

provides you the best grip.

5. Tighten the wing nut until the D-handle is secure.

Fig. 1

Bolt

Washer

Wing Nut

Tighten

Shaft Grip

D-Handle

Minimum 6 inches

(15.24 cm)

Shaft Housing

LT31C: Large D-handle

1. Remove the screws and bottom clamp piece that

were installed on the D-handle for shipping.

2. Place D-handle the over the shaft housing and onto

the bottom clamp (Fig. 2). Place it a minimum of

15.24 cm (6 inches) from the end of the shaft grip.

(4) Screws

Shaft

Housing

D-Handle

Bottom Clamp

Shaft Grip

Minimum 6 inches

(15.24 cm)

Fig. 2

3. Start screws with a large Flat-head or T-25 Torx

screwdriver. Do not tighten until you make the

handle adjustment.

4. If the D-handle was pre-installed, loosen the screws

on the handle just enough to move it.

5. While holding the unit in the operating position

(Fig. 27), maneuver the D-handle to the location that

provides you the best grip.

6. Tighten the clamp screws evenly, until the D-handle

is secure.

ASSEMBLY INSTRUCTIONS

INSTALL CUTTING ATTACHMENT SHIELD

Use the following instructions if the cutting attachment

shield on your unit is not installed. Use only the

instructions that apply to the type of shaft and shield that

your unit is equipped with.

LT31

1. Place the cutting attachment shield onto the shaft

housing. Be sure the guard mounting bracket slides

into the slot on the edge of the cutting shield. Rotate

the shield into place, counterclockwise. The holes in

the guard mounting bracket and cutting attachment

shield will line up (Fig. 5).

To prevent serious

personal injury,

never operate the trimmer without the

cutting attachment shield in place.

WARNING:

2. From inside the cutting attachment shield, push the square

bolt through the hole until the threaded end protrudes

through the guard mounting bracket (Fig. 6).

Guard

Mounting

Bracket

Shaft Housing

Square Bolt

Cutting Attachment

Shield

3. Put the washer on the bolt, then screw the wing nut

onto the bolt and tighten. Figure 7 shows the

installation process from underneath the unit.

Guard Mounting Bracket

Wing Nut

Cutting Attachment and Shield: Underside View

Cutting

Attachment

Shield

Wing Nut

Washer

Square Bolt

Washer

Hole

Fig. 5

Fig. 6

Fig. 7

LT31C

1. Place the cutting attachment shield onto the shaft

housing above the clamp assembly (Fig. 8).

2. Push the cutting attachment shield down to the top of

the cutting attachment assembly and then rotate the

cutting attachment shield until the screw holes align and

the guard fits into the recessed pocket (Fig. 9)

3. Install the four (4) screws with a Phillips screwdriver

(Fig. 10).

Shaft Housing

(4) Screws

Clamp

Assembly

Cutting

Attachment

Assembly

Cutting Attachment

Shield

Recessed

Pocket

Fig. 8

Fig. 9

Fig. 10

Install the cutting attachment shield when using

the unit as a grass trimmer

Install the cutting attachment shield on the shield mount

by inserting the three (3) screws into the shield mount.

Tighten securely with a flat blade screwdriver (Fig. 14).

LT31CS ONLY:

REMOVE THE CUTTING

ATTACHMENT AND INSTALL THE CUTTING

BLADE

NOTE: To make cutting blade removal and installation easier,

place the unit on the ground or on a work bench

Remove the Cutting Attachment Shield

See Remove and Install the Cutting Attachment Shield.

(3) Screws

Cutting

Attachment

Shield

Shield Mount

Gear Housing

Fig. 14

The gear housing

gets hot with use. It

can result in injury to the operator. The

housing remains hot for a short time even

after the unit is turned off. Do not touch the

gear housing until it has cooled.

WARNING:

To avoid serious

personal injury, the

cutting attachment shield MUST be in place

at all times while operating the unit as a

grass trimmer.

WARNING:

LT31CS ONLY: INSTALL THE HARNESS

1. Push the strap through the center of the buckle.

2. Pull the strap over the cross bar and down through

the slot in the buckle (Fig. 11).

3. Put the harness on over head and onto shoulder.

Snap it on to the support fitting (Fig. 12).

4. Adjust length to fit the operator’s size. Pull tab to

lengthen, pull strap to shorten (Fig 13).

Support Fitting

Fig. 11

Fig. 12

Fig. 13

LT31CS ONLY: REMOVE AND INSTALL THE

CUTTING ATTACHMENT SHIELD

Remove the cutting attachment shield when

using the unit as a brushcutter

Remove the cutting attachment shield from the shield

mount by removing the three (3) screws with a flat blade

screwdriver (Fig. 14). Store parts for future use.

The cutting

attachment shield

should NOT be installed when operating the

unit with a blade. Remove the cutting

attachment shield before removing or

installing the blade.

WARNING:

Always use the

shoulder harness

when using the cutting blade to avoid

serious personal injury.

WARNING:

BRUSHCUTTER ASSEMBLY INSTRUCTIONS

Cutting Attachment

Locking Rod

Slot

Locking Rod

Shaft Bushing Hole

Locking Rod Slot

Output Shaft

Bushing

Locking Rod

Output Shaft

2. Hold the locking rod in place by grasping it next to

the boom of the unit (Fig. 16).

3. While holding the locking rod, remove the cutting

attachment by turning it clockwise off of the output shaft

(Fig. 17). Store the cutting attachment for future use.

NOTE: The blade retainer under the cutting attachment

will be used when installing the cutting blade.

Fig. 15

Fig. 17

Fig. 16

Install the Cutting Blade

4. Place the cutting blade on the output shaft bushing

(Fig. 18).

Shield

Mount

Locking Rod

Cutting

Blade

Blade Retainer

Nut

Output Shaft

Bushing

Pilot Hole

Fig. 18

To avoid serious

personal injury,

always wear gloves while handling or

installing the blade.

WARNING:

Remove the Cutting Attachment

Align the shaft bushing hole with the locking rod slot and

insert the locking rod into the shaft bushing hole (Fig. 15).

Fig. 19

Pilot Step

5. Make sure that the cutting blade is centered on the

pilot step and sitting flat against the output shaft

bushing (Fig. 19).

If the cutting blade

is off-center, the

unit will vibrate and the blade may fly off,

causing possible serious personal injury.

WARNING:

Fig. 22

LT31CS ONLY: REMOVE THE CUTTING

BLADE AND INSTALL THE CUTTING

ATTACHMENT

Remove the Cutting Blade

1. Align the shaft bushing hole with the locking rod slot

and insert the locking rod into the bushing hole (Fig. 15).

Fig. 20

9. Remove the locking rod from the locking rod slot.

1/4-1/2 turn

Counterclockwise

6. Align the shaft bushing hole with the locking rod

slot and insert the locking rod into the bushing hole

(Fig. 15).

7. Put the blade retainer and nut on the output shaft.

Make sure that the blade is installed correctly.

8. Tighten nut counterclockwise against the blade while

holding the locking rod:

• If using a torque wrench and an 5/8 inch socket tighten

to: 37 - 38 N•m, 27 - 28 ft.•lb, 325 - 335 in•lb.

•Without a torque wrench, use a 5/8 inch closed-end or

socket wrench, turning the nut until the blade retainer

is snug against the shaft bushing. Make sure that the

blade is installed correctly, then rotate the nut an

additional 1/4 to 1/2 turn counterclockwise (Fig. 20).

Cutting Attachment

Locking Rod

Clockwise

6. Remove the locking rod.

7. Install the cutting attachment shield. Refer to Remove

and Install the Cutting Attachment Shield.

Blade Retainer

Output Shaft

Bushing

Fig. 21

BRUSHCUTTER ASSEMBLY INSTRUCTIONS

4. Remove the nut, blade retainer and blade. Store the

nut and blade together for future use in a secure

place. Store out of children’s reach.

Install the Cutting Attachment

Align the shaft bushing hole with the locking rod slot and

insert the locking rod into the shaft bushing hole (Fig. 15).

Place the blade retainer on the output shaft with the flat

surface against the output shaft bushing (Fig. 22). Screw

the cutting attachment counterclockwise onto the output

shaft. Tighten securely.

NOTE: The blade retainer must be installed on the output

shaft in the position shown for the cutting

attachment to work correctly.

To avoid serious

personal injury,

always wear gloves while handling or

installing the blade.

WARNING:

Do not sharpen the

cutting blade.

Sharpening the blade can cause the blade tip

to break off while in use. This can result in

severe personal injury. Replace the blade.

WARNING:

To avoid serious

personal injury or

damage to the unit, do not start or operate this

unit with the locking rod in the locking rod slot.

WARNING:

To avoid serious

personal injury, the

cutting attachment shield MUST be in place at

all times while operating the unit as a trimmer.

WARNING:

2. Hold the locking rod in place by grasping it next to

the boom of the unit (Fig. 21).

3. While holding the locking rod, loosen the nut on the

blade by turning it clockwise with a 5/8 inch closed-

end or socket wrench (Fig. 21).

OIL AND PETROL INFORMATION

NOTE: Dispose of the old petrol/oil mix in accordance to

Federal, State and Local regulations.

OIL AND PETROL MIXING INSTRUCTIONS

Old and/or improperly mixed fuel are the main reasons

for the unit not running properly. Be sure to use fresh,

clean unleaded petrol. Follow the instructions carefully

for the proper petrol/oil mixture.

Definition of Blended Petrols

Today's petrols are often a blend of petrol and

oxygenates such as ethanol, methanol, or MTBE (ether).

Alcohol-blended petrol absorbs water. As little as 1%

water in the petrol can make petrol and oil separate. It

forms acids when stored. When using alcohol-blended

petrol, use fresh petrol (less than 60 days old).

Using Blended Petrols

If you choose to use a blended petrol, or its use is

unavoidable, follow recommended precautions:

• Always use the fresh fuel mix explained in your

operator's manual

• Always agitate the fuel mix before fueling the unit

• Drain the tank and run the engine dry before storing

the unit

Using Fuel Additives

The bottle of 2-cycle oil that came with your unit

contains a fuel additive which will help inhibit corrosion

and minimize the formation of gum deposits. It is

recommended that you use our 2-cycle oil with this unit.

If unavailable, use a good 2-cycle oil designed for

air-cooled engines along with a fuel additive, such as

STA-BIL

Petrol Stabilizer or an equivalent. Add 23 ml

(0.8 oz) of fuel additive per gallon of fuel according to the

instructions on the container. NEVER add fuel additives

directly to the unit's fuel tank.

Thoroughly mix the proper ratio of 2-cycle engine oil

with unleaded petrol in a separate fuel can. Use a 40:1

petrol/oil ratio. Do not mix them directly in the engine

fuel tank. See the table below for specific petrol and oil

mixing ratios.

NOTE: 3.8 liters (1 gallon) of unleaded petrol mixed with

one 95 ml (3.2 oz) bottle of 2-cycle oil makes a

40:1 petrol/oil ratio.

UNLEADED PETROL 2 CYCLE OIL

3.8 LITERS

1 GALLON US

95 ml

3.2 FL. OZ

1 LITER 25 ml

MIXING RATIO - 40:1

Add fuel in a clean,

well ventilated

outdoor area. Wipe up any spilled fuel

immediately. Avoid creating a source of

ignition for spilt fuel. Do not start the engine

until fuel vapors dissipate.

WARNING:

Petrol is extremely

flammable. Ignited

Vapors may explode. Always stop the

engine and allow it to cool before filling the

fuel tank. Do not smoke while filling the

tank. Keep sparks and open flames at a

distance from the area.

WARNING:

Remove fuel cap

slowly to avoid injury

from fuel spray. Never operate the unit

without the fuel cap securely in place

WARNING:

For proper engine

operation and

maximum reliability, pay strict attention to

the oil and petrol mixing instructions on the

2-cycle oil container. Using improperly mixed

fuel can severely damage the engine.

CAUTION:

STARTING/STOPPING INSTRUCTIONS

Operate this unit only in a

well- ventilated outdoor

area. Carbon monoxide exhaust fumes can be lethal in

a confined area.

WARNING:

Avoid accidental starting.

Make sure you are in the

starting position when pulling the starter rope

(Fig. 26).

To avoid serious injury, the operator and unit

must be in a stable position while starting.

WARNING:

Start/On (I)

Stop/Off (O)

Fig. 25

Blue Choke Lever

Position 1

Position 3

Position 2

Primer Bulb

STARTING INSTRUCTIONS

STOPPING INSTRUCTIONS

1. Release your hand from the throttle control. Allow the engine

to cool down by idling.

2. Put the On/Off Stop Control in the OFF (O) position.

1. Mix petrol with oil. Fill fuel tank with petrol/oil mixture.

See Oil and Petrol Mixing Instructions.

2. Make sure the On/Off Stop Control in the ON ( I )

position (Fig. 23 or Fig. 24).

3. Fully press and release the primer bulb 10 times,

slowly. Some amount of fuel should be visible in the

primer bulb and fuel lines (Fig. 25). If you can’t see fuel

in the bulb, press and release the bulb as many times

as it takes before you can see fuel in it.

4. Place the blue choke lever in Position 1 (Fig. 25).

5. Crouch in the starting position (Fig. 26) and squeeze the

throttle control. Pull the starter rope 5 times.

6. Place the blue choke lever in Position 2.

7. While squeezing the throttle control (hold the throttle

lock-out also for the LT31CS model), pull the starter

rope out with a controlled and steady motion 1 to 4

times to start the engine.

NOTE: The unit uses Advanced Starting Technology™,

which significantly reduces the effort required to start

the engine. You must pull the starter rope out far

enough to hear the engine attempt to start. There is

no need to pull the rope briskly-- there is no harsh

resistance when pulling. Be aware that this starting

method is vastly different from (and much easier

than) what you may be used to.

8. Keep the throttle squeezed and allow the engine to

warm up for 15 to 30 seconds.

9. Place the blue choke lever in Position 3. The unit is

ready for use.

IF... The engine does not start, go back to step 3.

IF... The engine fails to start after a few attempts, place

the choke lever in Position 3 and squeeze the throttle

control. Pull the starter rope briskly 3 to 8 times. The

engine should start. If not, repeat.

IF WARM... If the engine is already warm, make sure the

On/Off Stop control is in the ON position and start the

unit with the blue choke lever in Position 2. After the

unit starts, move the blue choke lever to Position 3.

Fig. 26

Start/On (I) Stop/Off (O)

Throttle

Lock-Out

(LT31CS Only)

Throttle

Control

Fig. 24

Throttle Control

(Squeeze during a

standard start)

Trimmer

Equipped With

Advanced Starting

Technology™

Fig. 23

LT31

LT31C &

LT31CS

HOLDING THE TRIMMER

Before operating the unit, stand in the operating position

(Fig. 27). Check for the following:

• The operator is wearing eye protection and proper

clothing

• With a slightly-bent right arm, the operator’s right hand

is holding the shaft grip

• The operator’s left arm is straight, the left hand holding

the handle

• The unit is at waist level

• The cutting attachment is parallel to the ground and

easily contacts the grass without the need to bend over

After you start the unit and once you are in the operating

position, hook the shoulder strap to the unit (LT31CS only).

OPERATING INSTRUCTIONS

Fig. 27

ADJUSTING TRIMMING LINE LENGTH

The Bump Head™ cutting attachment allows you to

release trimming line without stopping the engine. To

release more line, lightly tap the cutting attachment on the

ground (Fig. 28) while operating the trimmer at high speed.

NOTE: Always keep the trimming line fully extended.

Line release becomes more difficult as the cutting

line becomes shorter.

Each time the head is bumped, about 1 inch (25.4 mm) of

trimming line is released. A blade in the cutting

attachment shield will cut the line to the proper length if

excess line is released.

For best results, tap the Bump Head™ on bare ground or

hard soil. If line release is attempted in tall grass, the

engine may stall. Always keep the trimming line fully

extended. Line release becomes more difficult as the

cutting line becomes shorter.

NOTE: Do not rest the Bump Head™ on the ground

while the unit is running.

Fig. 28

Some line breakage will occur from:

• Entanglement with foreign matter

• Normal line fatigue

• Attempting to cut thick, stalky weeds

• Forcing the line into objects such as walls or fence posts

TIPS FOR BEST TRIMMING RESULTS

• For best trimming results, operate unit at full throttle.

• Keep the cutting attachment parallel to the ground.

• Do not force the cutting attachment. Allow the tip of

the line to do the cutting, especially along walls.

Cutting with more than the tip will reduce cutting

efficiency and may overload the engine.

• Cut grass over 8 inches (200 mm) by working from top

to bottom in small increments to avoid premature line

wear or engine drag.

• Cut in the following manner, depending on your unit.

This improves the unit's cutting efficiency. Clippings

are thrown away from the operator.

• LT31CS: cut from left to right

• LT31 & LT31C: cut from right to left

• Slowly move the trimmer into and out of the cutting

area at the desired height. Move either in a forward-

backward or side-to-side motion. Cutting shorter

lengths produces the best results.

• Trim only when grass and weeds are dry.

• The life of your cutting line is dependent upon:

• Proper adherence of explained trimming techniques

• What vegetation is cut

• Where vegetation is cut

For example, the line will wear faster when trimming against

a foundation wall as opposed to trimming around a tree.

Do not remove or alter

the line cutting blade

assembly. Excessive line length will make the

clutch overheat. This may lead to serious

personal injury or damage to the unit.

CAUTION:

Always wear eye,

hearing, foot and

body protection to reduce the risk of injury

when operating this unit.

WARNING:

Trimmer

Brushcutter

Fig. 29

Fig. 30

DECORATIVE TRIMMING

Decorative trimming is accomplished by removing all

vegetation around trees, posts, fences and more.

Rotate the whole unit so that the cutting attachment is at

a 30° angle to the ground (Fig. 29).

LT31CS ONLY: USING THE CUTTING

BLADE

Before operating the unit with the cutting blade, stand in

the operating position (Fig. 30). Refer to Holding the

Trimmer.

Cutting Blade Operating Tips

To establish a rhythmic cutting procedure:

• Plant feet firmly, comfortably apart.

• Bring the engine to full throttle before entering the

material to be cut. At full throttle the blade has

maximum cutting power and is less likely to bind, stall

or cause blade thrust (which can result in serious

personal injury to the operator or others).

• Cut while swinging the upper part of your body from

left to right.

• Always release the throttle trigger and allow the engine

to return to idle speed when not cutting.

• When you are finished, always unsnap the unit from

the harness before taking off the harness.

• Swing the unit in the opposite direction as the blade

spins, which increases the cutting action.

• After the return swing, move forward to the next area

to be cut plant your feet again.

• The cutting blade is designed with a second cutting

edge. You can use it by removing the blade, turning it

upside down, and reinstalling it.

To reduce the chance of material wrapping around the

blade, follow these steps:

• Cut at full throttle

• Swing the unit into material to be cut from your left to

your right (Fig. 30)

• Avoid the material just cut as you make the return swing

OPERATING INSTRUCTIONS

Always wear eye,

hearing, foot, body

protection and the shoulder strap to reduce the

risk of injury when operating this unit.

WARNING:

Do not use the

cutting blade for

edging or as an edger. Severe personal injury

to yourself or others can result.

WARNING:

The blade continues

to spin after the

engine is turned off. The coasting blade can

seriously cut you if accidentally touched.

WARNING:

Do not sharpen the

cutting blade.

Sharpening the blade can cause the blade tip

to break off while in use. This can result in

severe personal injury to yourself or others.

Replace the blade.

WARNING:

ade thrust may

occur when the

spinning blade contacts an object that it does

not immediately cut. Blade thrust can be violent

enough to cause the unit and/or operator to be

propelled in any direction, and possibly lose

control of the unit. Blade thrust can occur

without warning if the blade snags, stalls or

binds. This is more likely to occur in areas where

it is difficult to see the material being cut.

WARNING:

Do not clear away

any cut material with

the engine running or blade turning. To avoid

serious personal injury, turn off the engine.

Allow the blade to stop before removing

materials wrapped around the blade shaft.

WARNING:

MAINTENANCE SCHEDULE

Perform these required maintenance procedures at the

frequency stated in the table. These procedures should

also be a part of any seasonal tune-up.

NOTE: Some maintenance procedures may require

special tools or skills. If you are unsure about

these procedures take your unit to any non-road

engine repair establishment, individual or

authorized service dealer.

NOTE: Maintenance, replacement, or repair of the

emission control devices and system may be

performed by any non-road engine repair

establishment, individual or authorized service

dealer.

In order to assure peak performance of your engine,

inspection of the engine exhaust port may be necessary

after 50 hours of operation. If you notice lost RPM, poor

performance or general lack of acceleration, this service

may be required. If you feel your engine is in need of this

inspection, refer service to any non-road engine repair

establishment, individual or authorized service dealer for

repair. DO NOT attempt to perform this process yourself

as engine damage may result from contaminants

involved in the cleaning process for the port.

FREQUENCY MAINTENANCE REQUIRED REFER TO

Before starting engine Fill fuel tank with fresh fuel Page 15

Every 10 hours Clean and re-oil air filter Page 26

Every 25 hours

Check and clean spark arrestor

Check spark plug condition and gap

Page 27

Page 28

Every 50 hours

Inspect exhaust port and spark arrestor screen for clogging or

obstruction to assure maximum performance levels

Page 27

MAINTENANCE AND REPAIR INSTRUCTIONS

To prevent serious

injury, never perform

maintenance or repairs with unit running.

Always service and repair a cool unit.

Disconnect the spark plug wire to ensure that

the unit cannot start.

WARNING:

This section covers both SplitLine™ and standard single

line installation.

Always use original equipment manufacturer 2.03 mm

(0.080 in) replacement line. Line other than the specified

may make the engine overheat or fail.

There are two methods to replace the trimming line:

• Wind the inner reel with new line

• Install a prewound inner reel

Winding the Existing Inner Reel

1. Hold the outer spool with one hand and unscrew the

Bump Knob™ counterclockwise (Fig. 31). Inspect the

bolt inside the Bump Knob to make sure it moves

freely. Replace the Bump Knob if damaged.

2. Remove the inner reel from the outer spool (Fig. 32).

Bump Knob™

Bolt

Fig. 31

Inner Reel

Spring

Outer Spool

Indexing Teeth

Fig. 33

Fig. 32

Never use metal-

reinforced line, wire,

chain or rope. These can break off and

become dangerous projectiles.

WARNING:

LINE INSTALLATION

Your trimmer is equipped with one of three cutting

attachments. Refer only to the section that applies to the

type of cutting attachment that your unit is equipped with.

LT31 LINE INSTALLATION: SMALL BUMP HEAD

3. Remove spring from the inner reel (Fig. 32).

4. Use a clean cloth to clean the the inner reel, spring,

shaft, and inner surface of the outer spool.

5. Check the indexing teeth on the inner reel and outer

spool for wear (Fig. 33). If necessary, remove burrs

or replace the reel and spool.

MAINTENANCE AND REPAIR INSTRUCTIONS

Fig. 38

Fig. 34

NOTE: SplitLine™ can only be used with the inner reel

with the slotted holes. Single line can be used on

either type of inner reel. Use Figure 34 to identify

the inner reel you have.

NOTE: Always use the correct line length when installing

trimming line on the unit. The line may not release

properly if the line is too long.

Single Line Installation

Go To Step 8 for SplitLine™ Installation

6. Take approximately 6 m (20 feet) of new trimming

line, loop it into two equal lengths. Insert each end of

the line through one of the two holes in the inner reel

(Fig. 35). Pull the line through the inner reel so that

the loop is as small as possible.

7. Wind the lines in tight even layers, onto the reel

(Fig. 36). Wind the line in the direction indicated on

the inner reel. Place your index finger between the

two lines to stop the lines from overlapping. Do not

overlap the ends of the line. Proceed to step 11.

SplitLine™ Installation

8. Take approximately 3 m (10 feet) of new trimming

line. Insert one end of the line through one of the two

holes in the inner reel (Fig. 37). Pull the line through

the inner reel until only about 4 inches is left out.

9. Insert the end of the line into the open hole in the

inner reel and pull the line tight to make the loop as

small as possible (Fig. 37).

10. Before winding, split the line back about 6 inches.

11. Wind the line in tight even layers in the direction

indicated on the inner reel.

NOTE: Failure to wind the line in the direction indicated will

cause the cutting attachment to operate incorrectly.

Slotted

Holes

For Use with SplitLine™

or Single Line

For Use with Single

Line ONLY

Holding Slots

12. Insert the ends of the line into the two holding slots

(Fig. 38).

13. Insert the ends of the line through the eyelets in the

outer spool and place inner reel with spring inside the

outer spool (Fig. 39). Push the inner reel and outer

spool together. While holding the inner reel and outer

spool, grasp the ends and pull firmly to release the

line from the holding slots in the reel.

Loop

Fig. 35

Fig. 36

Loop

Fig. 37

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MTD Yard Machines LT31 User manual

Brand: MTD

Model: Yard Machines LT31

Category: Grass trimmers

Type: User manual

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MTD Yard Machines LT31 User manual

MTD Yard Machines LT31 User manual

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